Cannot change font, size or anything for typewriter tool

Bon dia lorne17,
Perhaps you need to run a "repair" on Acrobat?

While the change options for Acrobat 8.x Pro/3D are not as fully featured
as those in Acrobat Pro Extended, both do have change options.

With either application I can consistently access the available choices in a fairly
straight forward manner.

Using Acrobat 3D (8.1.4)
Open the Typewriter toolbar. With the Hand tool selected, single click on a text string
entered earlier by the Typewriter tool. The cursor shape becomes up-down, left-right
arrows. Double Click.
The mouse pointer is now an "I-beam" and a blinking cursor line is present at the insertion point. Click-drag to select text.

The Typewriter toolbar's change options become accessible.
(text size and line spacing)
With the text string still selected, right click for the context menu. Go to the bottom
entry (Text Style) from which a secondary menu is presented for some choices for
text style.

Using Acrobat Pro Extended (9.1)
A similar approach. Hand tool > double click > use "I-beam" to click-drag for text selection.
Options for change are now accessible on the Typewriter toolbar.
Unlike Acrobat 8, you have font color, font type and font size as choices with
Acrobat 9.

Be well...